Phosphodiesterases are known to regulate cyclic AMP, and phosphodiesterase 4 (PDE4) has been shown to be the predominant regulator of cyclic AMP in respiratory smooth muscle and inflammatory cells. Inhibitors of PDE4 are useful in treating a variety of diseases, including allergic and inflammatory diseases, diabetes, central nervous system diseases, pain, and viruses that produce TNF.
Amino-substituted quinolyl PDE4 inhibitors are disclosed in U.S. Pat. No. 5,804,588; sulfonamide-substituted quinolyl PDE4 inhibitors are disclosed in U.S. Pat. No. 5,834,485; and (benzo-fused)heteroaryl-substituted PDE4 inhibitors are disclosed in U.S. Pat. No. 6,069,151. Oxazolyl-substituted quinolyl PDE4 inhibitors are disclosed in PCT/US2005/017134.
The compound referred to as Compound A herein, is described as its free base and pharmaceutically acceptable salt forms in WO2005/116009A1 on page 95, Example 26-347 and on page 228, claim 19; those descriptions are hereby incorporated by reference.